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Wiring Help needed asap!!!!

I have wiring for an overhead light that I've obviously messed up when disconnecting! The light is on a dimmer switch and is connected to other lights throughout the basement on 1 circuit. There are 3 white and 3 black wires, plus the ground inside the box. I believe the blacks were all together originally. I did notice when I took down the original fixture that it was connected to two white wires, not 1 black and one white. Also 2 of the white wires were together and one was alone, but I can't remember which!! How do I figure out the correct wiring, what tools do I need to determine which wires are live, etc.? Your speedy help would be very much appreciated!!!

BTW the metal plate, etc., to the left in the photo is the base plate and wires for the new fixture.

Re: Wiring Help needed asap!!!!

A volt -ohm meter ( multimeter ) readily available anywhere ( Canadian Tire for example ) is a very helpful tool .

More than likely the feed from the panel is coming into that box ---One cable with the black ( hot ) and white ( neutral ) conductors --- these should have constant 120 volts between them.

One cable with black ( hot ) and white ( neutral ) is extending to the other lights.
The white conductor and the lamp white would be connected to the above white conductor coming from the panel.

The third cable is more than likely coming from the switch. If you unscrew the switch from the wall box you will probably notice a black and white wire attached to the switch. In this case it is allowed by code to use the white wire as a feed and the black as the switch line to the lights. According to your recollection they may have reversed but the principle is the same.

Technically , the white conductor would be connected to the black feed ( supply ) from the panel at the ceiling box. The other end of that white conductor would connect to the supply terminal at the switch. This white wire should be identified with black electrical tape or a black marker to identify it as a *hot* conductor --- this will avoid any future confusion such as what you have here.

The black conductor of this cable would connect at the switch ( out ) and in the ceiling box connect to the black conductor of the lamp and to the black that extends to the other lights.

You are going to have to confirm :

- does the supply go to the ceiling box ?
if so , which cable has the constant 120 volts. Once identified cap them and with masking tape or white hockey tape mark "supply " and move them off to one side.
Then shut the breaker *off* to the circuit.

- does the switch have a black and white conductors connected ?
if so , which cable is it?

This where you would use the " ohm " feature on the mulimeter.

** warning --- first check for voltage on all wires before touching them.

Disconnect the the white and black wires from the switch --- connect them together at that point ( shorted together ). At the ceiling --- with your multimeter set on *ohms* check for zero ohms between the black and white pairs of the same cable.

Once you find them you now have -- through process of elimination -- identified the cable to extend to the other lights.
Again -- mark them with tape to identify them.

Re: Wiring Help needed asap!!!!

First, turn off the ***** to this circuit.

The following will most likely work IF there is only one cable (one black + one white wire) going into the switch box and it is NOT a 3-way switch. (Of course, the switch will be connected to two wires, but that's a red herring. We want to make sure that only one CABLE enters the BOX.)

First, make sure all light switches in the circuit are off. Unplug anything that's plugged into outlets on this circuit. Now, turn ON the switch for this light.

Take your meter, set to ohms or continuity, and test each pair of wires (each cable is a pair) entering into the light box. Only one pair should read zero ohms or indicate continuity. This pair is the one going to your light switch. To verify, turn the switch OFF; that pair should now read infinite ohms or no continuity.

Color the white wire of this pair black or red using a permanent marker or electrical tape to indicate that it's NOT a neutral (this is required by code). Connect the white (now marked red or black) to the black wire of the light fixture. Connect all of the black wires together. Connect all of the white wires, including the one from the light fixture, together.

Test your connections by tugging on each wire from the wire nut. If any come out, try again. There should be no exposed copper other than the ground wire.

The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.

Re: Wiring Help needed asap!!!!

Originally Posted by Fencepost

First, turn off the ***** to this circuit.

The following will most likely work IF there is only one cable (one black + one white wire) going into the switch box and it is NOT a 3-way switch. (Of course, the switch will be connected to two wires, but that's a red herring. We want to make sure that only one CABLE enters the BOX.)

First, make sure all light switches in the circuit are off. Unplug anything that's plugged into outlets on this circuit. Now, turn ON the switch for this light.

Take your meter, set to ohms or continuity, and test each pair of wires (each cable is a pair) entering into the light box. Only one pair should read zero ohms or indicate continuity. This pair is the one going to your light switch. To verify, turn the switch OFF; that pair should now read infinite ohms or no continuity.

I wrestled with posting doing it that way as well -- if it was a single pole toggle switch that would work just fine and is simple.However , there is a dimmer switch involved and the electronic dimming circuit could give a novice confusing continuity readings . By removing the 2 conductors from the dimmer switch and shorting them together assures a reliable continuity reading of of zero ( plus or minus 1 ) ohm .

Color the white wire of this pair black or red using a permanent marker or electrical tape to indicate that it's NOT a neutral (this is required by code). Connect the white (now marked red or black) to the black wire of the light fixture. Connect all of the black wires together. Connect all of the white wires, including the one from the light fixture, together.

Test your connections by tugging on each wire from the wire nut. If any come out, try again. There should be no exposed copper other than the ground wire.

Not to add more confusion to the OP -- personally I use the white ( marked with black tape or permanent marker ) conductor as a supply feed to the switch and use the black conductor as the switched leg to the lamp -- this avoids confusion in my mind.

Re: Wiring Help needed asap!!!!

Originally Posted by canuk

Not to add more confusion to the OP -- personally I use the white ( marked with black tape or permanent marker ) conductor as a supply feed to the switch and use the black conductor as the switched leg to the lamp -- this avoids confusion in my mind.

Yeah, but it took fewer words to say it my way.

The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.